1. Field of the Invention
The present invention relates to an electric switch for selective removal of a recording medium from a compound device which combines two pieces of equipment, such as a disk device and video device.
2. Related Art
Referring to FIG. 7, a compound device combines a video device and a disk device, and it has a cassette slot 51 and a disk slot 52 formed in its front panel 50. Also, the front panel 50 has a button switch 53 on the left side of the cassette slot 51, and another button switch 54 on the right side of the disk slot 52. Depression of the button switch 53 causes the cassette to appear from the cassette slot 51 whereas depression of the button switch 54 causes a disk tray to appear from the disk slot 54. When the compound device is loaded with a new cassette, the cassette is pushed in the cassette slot 51. When the compound device is loaded with a new disk, the disk is put on the tray, which appears from the disk slot 52. Then, the tray-and-disk is pushed in the disk slot 52.
FIG. 7(b) shows each switch 53, 54 in an exploded view. As shown, the switch comprises a push button 55a or 55b and a base plate 56a or 56b, on which a switching means 58a or 58b is fixed. Rectangular holes 57a and 57b are made in the front panel 50. The push buttons 55a and 55b are fitted in the rectangular holes 57a and 57b. Then, the base plates 56a and 56b are fixed to the front panel 50 with screws. When the push button 55a is depressed, the switching means 58a turns on, so that the cassette is pushed out of the cassette slot 51. Likewise, when the push button 55b is depressed, the switching means 58b turns on, so that the tray-and-disk is pushed out of the disk slot 52.
Arrangement of two switches on the front panel makes the compound device less attractive in appearance. Also, use of two switches disadvantageously increases the assembly work and accordingly the manufacturing cost of the compound device increases. The front panel with two rectangular holes requires a metal mold whose shape is rather complicated, and accordingly the metal mold costs much. At the final stage of assembly, the compound device must be checked in respect of whether these two switches can work normally. Accordingly, extra time is involved for checking at the final stage.
In the hope of solving such a problem, JP 7-211195(A) entitled “Seesaw Button Device” has proposed use of a dual switch. It comprises a base plate having two switches mounted thereon, a seesaw type of push button supported in the middle to move up and down by pushing one or the other end with finger, and an intermediate plate placed between the seesaw button and the base plate. The seesaw button has two push legs and two semicircular projections, which are formed at the middles of the opposite longitudinal sides of the button. Each push leg is long enough to reach the corresponding switch when the button is pushed and inclined down on one side. In the intermediate plate two apertures are made to allow the push legs to pass therethrough. Also, a semicircular fulcrum is formed in the middle of the intermediate plate, semicircular notches are made in the middles of the opposite longitudinal sides of the intermediate plate, and cantilever-like support pieces are integrally connected to the intermediate plate to extend half way in the apertures. The seesaw button is nested with the intermediate plate by putting the seesaw button on the semicircular fulcrum, inserting the push legs in the apertures to reach short of the switches and snapping the semicircular projections into the semicircular notches. In the horizontal position the seesaw button stays on the opposite cantilever-like support pieces. Finger-depression of the seesaw button on one side against the cantilever-like piece makes one of the push legs push the corresponding switch to turn on. Then, the associated drive mechanism moves the cassette, and it appears from the cassette slot of the front panel. Finger-depression of the seesaw button on the other side makes the other push leg push the corresponding switch to turn on. Then, the tray-and-disk will appear from the disk slot of the front panel. Release of the seesaw button allows it return to its original horizontal position under the influence of one or the other cantilever-like support piece.
To assure that the push button springs back to its original horizontal position when the finger is removed to release the push button, the cantilever-like support pieces need to have enough resilience. It is required that such cantilever-like support pieces be exactly sized and shaped, and be sometimes made of special metals. The resilient pieces are small compared with the front panel, and therefore, it is very difficult to make them into exact shape and size as required when the front panel having the cantilever-like pieces appearing halfway in its apertures is injection-molded. It is almost impossible to make a front panel whose cantilever-like pieces are of a material (or spring metal) which is different from that of the front panel. Such a resilient piece should neither be too strong in resilience to push the seesaw button without difficulty, nor too weak to make the seesaw button return to its original horizontal position. As a matter of fact it is practically impossible to injection-mold a front panel whose cantilever-like pieces extend halfway in its apertures.
In view of the above, one object of the present invention is to provide a dual switch for selective removal of a recording medium from a compound device, in which the button is self-repulsive enough to return to its original position after actuation, and thanks to the integral connection of spring means to the button, the spring means can be so exactly sized and shaped that the exact switching action may be assured.